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Biomedical subjects

R E Ashton

Publications and source records attributed to R E Ashton.

At least 19 recordsLinked to original sources
PubMed2001

The management of cutaneous leishmaniasis from Belize.

We report 20 patients who contracted cutaneous leishmaniasis in Central and South America, 18 of them in Belize. The diagnosis was confirmed by the polymerase chain reaction (PCR) in 79% of those tested; the corresponding figure for histology was 62%, touch smear 46%, and culture 11%. Results of PCR can be falsely positive, so treatment should not be based on PCR alone. Of the 20 cases 18 were healed 6 weeks after intravenous sodium stibogluconate 20 mg/kg per day for 20 days. We present a management protocol.

Adolescent↗
PubMed1999

Topical maxacalcitol for the treatment of psoriasis vulgaris: a placebo-controlled, double-blind, dose-finding study with active comparator.

1alpha, 25-Dihydroxy-22-oxacalcitriol (maxacalcitol) is a vitamin D3 analogue which displays approximately 10 times greater efficacy at suppressing keratinocyte proliferation in vitro than calcipotriol and tacalcitol. To determine clinical efficacy, a phase II double-blind, randomized, left vs. right, concentration-response study was performed with once-daily topical maxacalcitol in patients with mild to moderate chronic plaque psoriasis. Primary efficacy parameters were psoriasis severity index (PSI) based on sum of scores for erythema, scaling and induration and investigators' overall assessment of patients' response to therapy at 8 weeks of treatment. One hundred and forty-four patients participated. All concentrations of maxacalcitol ointment (6, 12.5, 25 and 50 microg/g) were significantly more effective at reducing PSI than placebo (P < 0.01), with greatest effect noted for maxacalcitol 25 microg/g. Calcipotriol ointment 50 microg/g once daily as active comparator had a similar effect. Marked improvement or clearance of psoriasis was greatest for maxacalcitol 25 microg/g (55% of subjects) which compared favourably with calcipotriol (46%). Improvement continued throughout the study period, with no plateau at week 8. Investigators' and patients' side preference (secondary efficacy parameters) rated maxacalcitol more effective than placebo and 25 microg/g maxacalcitol better than calcipotriol (P < 0.05 for investigators' assessment). Twelve patients withdrew from the study due to adverse events, of which four were judged to be due to study medication. This study indicates that once-daily maxacalcitol ointment is effective in the management of plaque psoriasis, with greatest effect noted at 25 microg/g. As no response plateau was noted at 8 weeks, these data suggest that further benefit might be obtained if maxacalcitol ointment were applied for longer. Finally, investigators' overall assessment and side preference suggest that maxacalcitol 25 microg/g may be more effective than once-daily calcipotriol.

Administration, Topical↗
PubMed1999

Reactivation of cutaneous leishmaniasis after surgery.

Cutaneous leishmaniasis (CL) is caused by a parasite from the genus Leishmania. Infection is transmitted to humans from the bite of sandflies. We describe an 85-year-old man who developed CL on his face after recent cutaneous surgery in that site. The case is also unusual because the most likely source of exposure to the infection occurred over 50 years previously. Polymerase chain reaction, slit-skin smear, serology and the leishmanin test were not helpful in diagnosis, which was confirmed by histopathological demonstration of the parasite.

Aged↗
PubMed1995

Teaching non-dermatologists to examine the skin: a review of the literature and some recommendations.

An international committee has recently decided on standard definitions of common dermatological terms. However, some inconsistencies remain. Those concerning the definitions of 'plaque' and 'patch' could be resolved by making the lower limit of size of these lesions 0.5 cm, to correlate with the proposed 0.5 cm upper limit of size of a macule and a papule. The practice of describing crust, scale, etc. as secondary lesions should be abandoned. Instead, the type of lesion (e.g. papule, plaque, nodule), and its surface features (e.g. scale, crust, etc.) should be described separately. The concept of smooth/normal as a surface feature should be included. A scheme is recommended for describing skin lesions, which is based on the following features: (i) their site, distribution and arrangement; (ii) lesion morphology, under the following headings: palpation, type, surface, colour, border, size, shape; and (iii) associated features, such as changes affecting the nails, mouth, scalp and genitals.

Dermatology↗
PubMed1992

DERMIS: a computer system for assisting primary-care physicians with dermatological diagnosis.

DERMIS is a computerized skin disease diagnostic prompting system which has been derived from the prospective study of 5203 cases. It has been designed for use by non-dermatologists such as general practitioners. The program produces a list of reasonable diagnoses based on probabilities calculated using Bayes' theorem. Out of 221 precise diagnoses made by the dermatologist in the clinic, 42 groupings were created to encompass the most common or important diseases encountered in general practice. Four 'remainder' or 'send to specialist' groups were included for the 13% of uncommon conditions. The program, when tested by 'one out' analysis on the original cases, placed the correct diagnosis first on 76% of occasions, and within the first three on 95% of occasions. In 76 of 125 cases randomly selected from the data base, a request for diagnostic assistance had been made by the referring general practitioner. It has been estimated that in 54 of these 76 cases the DERMIS system could have provided differential advice with the correct diagnosis appearing at the top of the list. The system has been written in MUMPS and runs on an IBM-compatible desk-top computer. The software allows real time data entry. Arrangements are in hand for performing clinical trials of the system in general practice. If current performance is maintained, and the response to the system's output is favourable, then DERMIS might well enhance performance in medical decision making for the benefit of patients, medical services and budget holders.

Diagnosis, Computer-Assisted↗
PubMed1986

Anti-androgen treatment in women with acne: a controlled trial.

Ninety female patients with acne were allocated randomly to one of three groups and treated either with Diane, a high dose cyproterone acetate (CPA) regime with ethinyloestradiol, or Minovlar. The same dose of oestrogen was common to all three treatment groups. Patients were assessed every 2 months for 6 months, by grading for severity of the acne, lesion counts and photography, and subjectively using a visual analogue scale. In addition, bacteriological sampling and sebum excretion rate (SER) measurements were performed. The results showed a clinical improvement in all three treatment groups, but a more rapid and complete response was seen in those groups who received CPA. There was also a consistent trend suggesting a more favourable response in those in the high dose CPA group. Although there was a marked reduction in SER in the groups treated with CPA, there was no correlation between reduction in SER and clinical improvement in individuals, nor could a reduction in the surface bacterial population be shown to be a primary event in the success of anti-androgen therapy. We have shown that the addition of CPA to oestrogen adds significantly to the therapeutic effect in acne and that anti-androgen and oestrogen combinations are more effective than standard oestrogen and progestagen contraceptive pills.

Acne Vulgaris↗
PubMed1986

A comparative study of the induction of epidermal hyperplasia by natural and synthetic retinoids.

Retinoids are potent inducers of epidermal hyperplasia. In the present study the ability to induce epidermal hyperplasia by a variety of retinoids has been compared. Thirteen retinoids and beta-carotene were applied topically in an acetone vehicle to the dorsal skin of hairless mice and the dose-response and time course for the induction of hyperplasia were measured. Peak hyperplasia occurred 4 to 5 days after a single topical dose, and was induced by doses well below those producing gross or histological signs of cutaneous toxicity. The induction of hyperplasia was dose-dependent, the number of epidermal cell layers increasing initially in proportion to the log of the dose and then tending to plateau or, in some cases decrease, after which further increases in dose were associated with the appearance of gross and histological toxicity. The slopes of the initial increasing phase were determined and potencies expressed as the dose producing a 50% increase in the number of epidermal cell layers. All-trans-retinoic acid and its analogs, etretinate and its free acid, (E)-4[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl- 2-naphthalenyl)-1-propenyl]-benzoic acid (arotinoid) derivatives, retinol and retinal produced an increase in the number of cell layers proportionate to the log of the dose. Decarboxylated (E)-4[2-(5,6,7,8-tetrahydro-5,5,8,8- -tetramethyl-2-naphthalenyl-1-propenyl]-benzoic acid, a cis-locked aryl triene derivative of retinoic acid and beta-carotene were inactive. Similar time courses were observed when retinoids were dosed p.o. The relative potencies of the retinoids in this system show similar trends to those reported for biological activities measured in other in vivo and in vitro assays.

Animals↗
PubMed1985

Juvenile plantar dermatosis. A clinicopathologic study.

Fifty-six patients had juvenile plantar dermatosis (JPD). The plantar surface of the toes and the anterior third of the sole were the sites most commonly affected. Less commonly affected were the dorsal surface of the toes and the fingertips. No seasonal variation was found, and treatment was generally ineffective. Preventative measures had no influence on the course of the condition. Histopathologic features included psoriasiform acanthosis, with focal loss of granular cell layer, and uniform parakeratosis. Distinctive features included a tendency for the dermal infiltrate to localize around sweat ducts at their point of entry into the epidermis. In addition, inflammatory changes within the epidermis were localized mainly to the acrosyringium and included paranuclear vacuolization of epidermal keratinocytes, spongiosis, and slight spongiotic vesiculation. These changes are similar to those described in other eczematous conditions, and there is little evidence to suggest that disordered sweating plays a primary role in the pathogenesis of JPD.

Adolescent↗
PubMed1984

Anthralin for psoriasis: short-contact anthralin therapy compared with topical steroid and conventional anthralin.

Anthralin is an effective topical drug for psoriasis therapy. Recent studies have suggested that anthralin may be effective in high concentrations for short periods of skin contact. The purpose of these studies was to compare psoriasis improvement rates in patients treated with 0.3% anthralin ointment for 10 minutes' skin contact daily with patients treated with a topical steroid, difluorosone diacetate. A further study conducted was a bilateral paired comparison between conventional strength (0.1%-0.5%) anthralin ointment overnight with high concentration anthralin (0.5%-3%) for short contact periods of 10 minutes daily. The results showed good responses in all treatment groups. Short-contact anthralin is confirmed as a practical means of outpatient therapy for psoriasis.

Administration, Topical↗
PubMed1984

Histologic changes in the skin of the rhino mouse (hrrhhrrh) induced by retinoids.

The effects of four retinoids, all-trans-retinoic acid (RA), 13-cis-retinoic acid (13-cis-RA), aromatic retinoid, and arotinoid ethyl ester ( arotinoid ) were examined on the skin of the rhino mouse. Rhino mouse skin is characterized by the presence of keratin-containing utricles attached to the epidermis, and subcutaneous cysts, both of which are derived from hair follicles. The utricles were examined in horizontal sheets of epidermis, and in vertical histologic sections. After applications of 0.1 ml of 0.1% RA, 0.1% 13-cis-RA, 0.1% aromatic retinoid, or 0.001% arotinoid in acetone to the dorsal skin for 5 days a week for 2 weeks, there was a reduction of utricle diameter to 45%, 52%, 30%, and 31% of acetone-treated controls, respectively. Histologic examination of the epidermis revealed that a dose-dependent hyperplasia and thickening of the epidermis and the stratum granulosum was induced by the retinoids when given at subtoxic doses, being most marked after arotinoid or RA. The thickness of the walls of the utricles also increased with increasing dose of retinoid, paralleling the changes in the epidermis. After doses of 0.1% RA and 0.001% arotinoid , the utricles resembled the hair follicles of hairless mice. Hyperplasia of the epidermis appears to be a primary effect of retinoids or rhino mouse skin. Hyperproliferation of the utricle wall is accompanied by a reduction in the size of the utricle lumen, preceding eventual differentiation of the utricles to normal-looking pilar units.

Animals↗